(12) The levels of penalties in this Directive reflect the growing concern among Member States regarding the development of the phenomenon of trafficking in human beings. For this reason this Directive uses as a basis levels 3 and 4 of the Council conclusions of 24- 25 April 2002 on the approach to apply regarding approximation of penalties. When the offence is committed in certain circumstances, for example against a particularly vulnerable victim, the penalty should be more severe. In the context of this Directive, particularly vulnerable persons should include at least all children. Other factors that could be taken into account when assessing the vulnerability of a victim include, for example, gender, pregnancy, state of health and disability. When the offence is particularly grave, for example when the life of the victim has been endangered or the offence has involved serious violence such as torture, forced drug/medication usage, rape or other serious forms of psychological, physical or sexual violence, or has otherwise caused particularly serious harm to the victim, this should also be reflected in a more severe penalty. When, under this Directive, a reference is made to surrender, such reference should be interpreted in accordance with Council Framework Decision 2002/584/JHA of 13 June 2002 on the European arrest warrant and the surrender procedures between Member States ( 1 ). The gravity of the offence committed could be taken into account within the framework of the execution of the sentence.